Ignore false doxygen warnings

Doxygen cannot relate a function declaration to its matching definition,
and output warnings even though the declaration does not have
documentation.

Author: romainbrenguier

scripts/expected_doxygen_warnings.txt

@@ -1,3 +1,14 @@
+/home/travis/build/diffblue/cbmc/src/pointer-analysis/value_set.cpp:353: warning: no uniquely matching class member found for
+  void value_sett::get_value_set(exprt expr, std::list< exprt > &dest, const namespacet &ns) const
+Possible candidates:
+  std::vector< exprt > value_sett::get_value_set(exprt expr, const namespacet &ns) const' at line 276 of file /home/travis/build/diffblue/cbmc/src/pointer-analysis/value_set.h
+  object_mapt value_sett::get_value_set(exprt expr, const namespacet &ns, bool is_simplified) const' at line 480 of file /home/travis/build/diffblue/cbmc/src/pointer-analysis/value_set.h
+/home/travis/build/diffblue/cbmc/src/pointer-analysis/value_set.cpp:381: warning: no uniquely matching class member found for
+  void value_sett::get_value_set(exprt expr, object_mapt &dest, const namespacet &ns, bool is_simplified) const
+Possible candidates:
+  std::vector< exprt > value_sett::get_value_set(exprt expr, const namespacet &ns) const' at line 276 of file /home/travis/build/diffblue/cbmc/src/pointer-analysis/value_set.h
+  object_mapt value_sett::get_value_set(exprt expr, const namespacet &ns, bool is_simplified) const' at line 480 of file /home/travis/build/diffblue/cbmc/src/pointer-analysis/value_set.h
+
 /cbmc/src/solvers/miniBDD/miniBDD.cpp:402: warning: documented symbol `mini_bddt mini_bddt::operator &' was not declared or defined.
 /cbmc/src/solvers/sat/satcheck_glucose.cpp:228: warning: no matching class member found for 
   template <>